/*-----------------------------------------------------------------------------
* Copyright (C) 2010-2014 ARM Limited. All rights reserved.
*
* $Date:        19. March 2015
* $Revision: 	V.1.4.5
*
* Project: 	    CMSIS DSP Library
* Title:        arm_lms_norm_init_q15.c
*
* Description:  Q15 NLMS initialization function.
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
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*     notice, this list of conditions and the following disclaimer.
*   - Redistributions in binary form must reproduce the above copyright
*     notice, this list of conditions and the following disclaimer in
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*     distribution.
*   - Neither the name of ARM LIMITED nor the names of its contributors
*     may be used to endorse or promote products derived from this
*     software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* ---------------------------------------------------------------------------*/

#include "arm_math.h"
#include "arm_common_tables.h"

/**
 * @addtogroup LMS_NORM
 * @{
 */

/**
 * @brief Initialization function for Q15 normalized LMS filter.
 * @param[in] *S points to an instance of the Q15 normalized LMS filter structure.
 * @param[in] numTaps  number of filter coefficients.
 * @param[in] *pCoeffs points to coefficient buffer.
 * @param[in] *pState points to state buffer.
 * @param[in] mu step size that controls filter coefficient updates.
 * @param[in] blockSize number of samples to process.
 * @param[in] postShift bit shift applied to coefficients.
 * @return none.
*
* <b>Description:</b>
* \par
* <code>pCoeffs</code> points to the array of filter coefficients stored in time reversed order:
* <pre>
*    {b[numTaps-1], b[numTaps-2], b[N-2], ..., b[1], b[0]}
* </pre>
* The initial filter coefficients serve as a starting point for the adaptive filter.
* <code>pState</code> points to the array of state variables and size of array is
* <code>numTaps+blockSize-1</code> samples, where <code>blockSize</code> is the number of input samples processed
* by each call to <code>arm_lms_norm_q15()</code>.
*/

void arm_lms_norm_init_q15(
    arm_lms_norm_instance_q15 *S,
    uint16_t numTaps,
    q15_t *pCoeffs,
    q15_t *pState,
    q15_t mu,
    uint32_t blockSize,
    uint8_t postShift)
{
    /* Assign filter taps */
    S->numTaps = numTaps;

    /* Assign coefficient pointer */
    S->pCoeffs = pCoeffs;

    /* Clear state buffer and size is always blockSize + numTaps - 1 */
    memset(pState, 0, (numTaps + (blockSize - 1u)) * sizeof(q15_t));

    /* Assign post Shift value applied to coefficients */
    S->postShift = postShift;

    /* Assign state pointer */
    S->pState = pState;

    /* Assign Step size value */
    S->mu = mu;

    /* Initialize reciprocal pointer table */
    S->recipTable = (q15_t *) armRecipTableQ15;

    /* Initialise Energy to zero */
    S->energy = 0;

    /* Initialise x0 to zero */
    S->x0 = 0;

}

/**
 * @} end of LMS_NORM group
 */
